1. Department of Microbiology, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
2. Department of Biostatistics and Epidemiology, Faculty of Health, Environmental Health Research Center, Golestan University of Medical Sciences, Gorgan, Iran
3. Division of Paediatric and Adolescent Medicine, University of Oslo, Oslo, Norway
4. Department of Paediatrics and Adolescent Health, University of Botswana, Gaborone, Botswana
5. Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan, Iran